The use of a set of disposable pipette tips and the provision of a carrier therefor is well known. Typically, either a plate carrying a number of pipette tips, usually ninety-six, is provided or a number of such plates, often five, are provided in stacked form as a packaging convenience. In loading the tips for use, a single plate of tips is placed over a support structure (a support rack or another supportive plate of tips) and the tips, variably with or without the single plate, are released into the rack.
In many settings in which pipette tips are used, it is desirable to minimize the user's handling of the tips. However, most prior art tip mounting systems are not fully satisfactory in this regard primarily because in such systems, the tips are disposed somewhat loosely in the carrying plate. Thus, at several points of use, i.e., when the tips and the carrying plate are placed in a package for transport, lifted from such a package after transport using the carrying plate, or placed over a support structure using the carrying plate, the tips are susceptible to becoming displaced from the carrying plate and thus, to requiring manual repositioning in the carrying plate.
Most prior art tip mounting and disposal systems are further unsatisfactory in that they consist of unwieldy tip releasing devices. Particularly problematic are prior art systems in which the loosely disposed tips are automatically released when the carrying plate is placed over the support rack. With such systems, the user is undesirably prevented from controlling the carrying plate between a tip-carrying and a tip-releasing position. This lack of user control results in the tips being prematurely displaced from the carrying plate by a simple jolt or contact. More specifically, premature displacement often occurs during placement over the support structure when the tips are not precisely aligned with tip-receiving apertures of the support. Such precise alignment is extremely difficult to achieve with most existing loose-tip systems. It is therefore desirable to provide a tip mounting and disposal apparatus that is easy to use and allows the user to control the tip-holding and tip-releasing functions thereof.
Prior to the present invention, it has been observed that when a user is removing a tip from a tip holder, the tip holder may be inadvertently lifted relative to a tip support so that it requires repositioning before use is resumed. Such inadvertent lifting may occur, for example, when a tip or a row of tips is being removed at an angle other than perpendicular to the tip support. It has also been observed that when a user is removing a pipette tip assembly from an assembly container or assembly packaging, the tip holder may be inadvertently lifted relative to the tip support. Such inadvertent lifting may occur, for example, by virtue of a container lid catching on a front edge of the tip holder when the container is opened. When the tip holder is so lifted, typically the user must handle the system to reposition the tip holder and any displaced tips. It is therefore desirable to provide a pipette tip mounting and transfer apparatus in which the tip holder may be maintained in a tip-releasing position until it is selectively moved from that position.